<s>
Model-based	B-Application
specification	I-Application
is	O
an	O
approach	O
to	O
formal	B-Application
specification	I-Application
where	O
the	O
system	O
specification	B-Application
is	O
expressed	O
as	O
a	O
system	O
state	O
model	O
.	O
</s>
<s>
The	O
most	O
widely	O
used	O
notations	O
for	O
developing	O
model-based	B-Application
specifications	I-Application
are	O
VDM	B-Application
and	O
Z	B-Language
(	O
pronounced	O
Zed	O
,	O
not	O
Zee	O
)	O
.	O
</s>
<s>
Another	O
well-known	O
approach	O
to	O
formal	B-Application
specification	I-Application
is	O
algebraic	B-Application
specification	I-Application
.	O
</s>
